Which of the following properties characterizes Mycoplasmas?
A. Filtrable through bacterial filters
B. Resistant to penicillin and tetracycline
C. Resistant to penicillin, susceptible to tetracycline
D. Resistant to tetracycline, susceptible to penicillin
E. Highly pleomorphic
Choose the correct answer from the options given below:
A. Filtrable through bacterial filters
B. Resistant to penicillin and tetracycline
C. Resistant to penicillin, susceptible to tetracycline
D. Resistant to tetracycline, susceptible to penicillin
E. Highly pleomorphic
Choose the correct answer from the options given below:
Show Hint
- B, E only
- A, C, E only
- A, B, E only
- A, D, E only
The Correct Option is B
Solution and Explanation
Mycoplasmas (class Mollicutes, including Phytoplasmas and Spiroplasmas) are specialized wall-less prokaryotic microorganisms.
Step 2: Detailed Explanation:
Evaluating the cellular and physiological characteristics of Mycoplasmas:
1. Lack of rigid peptidoglycan cell wall: Enclosed only by a flexible, sterol-rich trilaminar plasma membrane, making them highly pleomorphic (Statement E) and capable of passing through standard bacterial retention filters (0.45 $\mu$m) (Statement A).
2. Antibiotic sensitivity: Because they completely lack peptidoglycan cell walls, they are naturally resistant to $\beta$-lactam antibiotics like penicillin (which inhibit transpeptidase cell wall synthesis), but are susceptible to broad-spectrum protein synthesis inhibitors such as tetracycline (Statement C).
Statements B and D are therefore incorrect.
Step 3: Final Answer:
Hence, the characterizing properties are A, C, and E only.
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